1. Field of the Invention
The present invention relates to control systems for regulating computer systems and other electronic systems.
2. Description of the Related Art
Control systems are used to regulate variable parameters of electronic systems. For example, control systems have been devised to regulate environmental variables such as temperature and sound level in a computer system, as well as performance-related variables such as electrical power and current consumption of the system. Generally, a control system monitors the current state of the system and compares it to the desired state of the system. The deviation from the desired state, often referred to as the error, is used to compute a new control input to the system. The term “control loop” may be used to describe the path of the signals that form this feedback. Frequently, a component of a computer system may affect multiple system parameters. For example, a processor's activity level may influence temperature, current flow, power consumption, and even (indirectly, through its effect on fan speed) sound levels in a computer system. Thus, multiple control systems may each seek to regulate the same component, which can present conflicting demands to the component.
If the component accepts any request or instruction to operate at given level, then the component performance may vary dramatically according to the latest input received. This can lead to unstable control loops for each of the control systems or management entities and various undesirable results. For example, if the control systems do not adequately manage the temperature of the processor, a built-in thermal protection mechanism can cause a catastrophic shut-down of the entire chip.
An improved control system and method are therefore needed for resolving potentially competing demands of multiple control loops in an electronic system. It would be desirable if the control system and method provided individual control of system components giving consideration to multiple control loops.